1. Technical Field
This invention relates to the art of making platinum catalysts useful in the conversion of hydrocarbons contained within the exhaust stream of an internal combustion engine, and more particularly to the use of amino Polymers for enhancing the conversion efficiency of catalyst metals.
2. Discussion of the Prior Art
Platinum containing chlorine compounds (i.e., chloroplatinic acid, ammonium chloroplatinate, and platinum chloride) have been used in the making of oxidation catalysts for some time. Such materials are economical and are used extensively in commercial fabrication of automotive catalysts. It is known that platinum-amines (along with other metal amines, the metal being of group VIII of the periodic table) tend to be more conversion efficient for oxidizing hydrocarbons. However, such platinum-amines unfortunately must be permanently bonded to the catalyst metal and the resulting polymer bonded catalysts are low temperature materials which cannot be used in the high temperature experienced in automotive applications (see U.S. Pat. Nos. 4,098,727; 4,179,402; 4,179,403; 4,306,085; and 4,526,884).
It would be desirable to obtain the same or better levels of conversion efficiency in a catalyst prepared with the economy of platinum/chloride compounds and without the need for permanent bonding of amine polymers.